Arrangement for the active adjustment of a motor vehicle wheel

ABSTRACT

An arrangement for the active adjustment of a motor vehicle wheel includes a device which has an adjusting element and in which the suspension links, independently of this device, are linked below and/or above a wheel spin axis to a wheel carrier and are pivotally held on the vehicle body. The device has an adjusting element which is connected with the wheel carrier by means of a tie rod. For forced wheel position adjustments as a function of driving parameters, the adjusting element can be adjusted about a swivel axis formed below the wheel spin axis by a wheel-carrier-side tie rod joint and a wheel-carrier-side link joint. The adjusting element of the device includes at least one hydraulic cylinder which is constructed so that it can be moved in and out while influencing the wheel adjustment by way of an electronic control unit 40 as a function of driving parameters, such as the suspension travel, the lateral acceleration, the speed, the longitudinal acceleration, the deceleration, the yawing moment, and the steering angle.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to an arrangement for the active adjustment of amotor vehicle wheel having an adjusting element, suspension links linkedto a wheel carrier, and an intermediate element for linking theadjusting element and the suspension links to the wheel carrier.

A wheel, suspension system disclosed in DE-PS 31 39 792 which shows anadjusting device for the camber change and the toe change under certaindriving conditions. The adjustment takes place by way of hydrauliccylinders which are partially integrated into the link therebetween orwhich are formed as part of the wheel suspension link or as part of thelink bearing. The adjustment elements are consequently subjected torelatively high forces which otherwise are absorbed only by the linkbearings.

In Patent Document GB-A-2 203 711, an arrangement using a connectinglink is shown for the control of the camber of the rear wheels forvehicles with four steerable rear wheels. This connecting link ispivotally fastened to the vehicle body and has a central swivel bearingfor a suspension link supported and disposed on the wheel carrier. Ahydraulic cylinder, which is constructed as an adjusting element andwhich causes the camber change of the wheel by way of the connectinglink, is applied to the lower end of the connecting link facing awayfrom the bearing of the body.

It is an object of the invention to provide a wheel suspension systemfor a motor vehicle which has a wheel adjusting device that requireslittle space, has a favorable response characteristic and is not subjectto excessive forces.

According to the invention, this object is achieved by an arrangementfor the active camber and/or toe adjustment of a motor vehicle wheel bya way of and adjusting device comprising an adjusting element in whichsuspension links are linked to a wheel carrier, are swivellably held onthe vehicle body and the adjusting element, by way of a connectingintermediate element, is connected with the wheel carrier while actingupon it in an adjusting manner, wherein the intermediate element, by wayof a central ball joint, is linked directly to the wheel carrier in atiltable manner, and a control rod of the adjusting device is connectedwith a first bearing, and the suspension link is connected with a secondbearing, the adjusting device comprising a hydraulic adjusting elementwhich is connected with the control rod and being constructed to becapable of moving in and out while influencing the position of the wheelby way of an electronic control unit for forced wheel position changesas a function of driving parameters, such as suspension travel, lateralacceleration, the speed, the longitudinal acceleration, deceleration,yawings and steering angles and wherein the wheel is adjustable about aswivel axis formed below the wheel spin axis by a wheel-carrier-side tierod joint and a wheel-carrier-side link joint.

According further to the present invention, the control rod can be heldon the intermediate element which is linked to the wheel carrier andwhich holds on its upper free end the control rod in the swivel bearingwith an axis in an articulated manner, and supports on its lower freeend the suspension in the bearing with a swivel axis.

According further to the present invention, the control rod can be heldon an intermediate element which is linked to the wheel carrier andwhich supports on an upper free end of the intermediate element thesuspension link in the swivel bearing and holds on a lower free end ofthe intermediate element the control rod in the bearing in anarticulated manner.

According further to present invention, between the adjusting elementand the control rod, an intermediate lever is arranged which comprisestwo arms which are disposed at an angle with respect to one another. Theintermediate lever with the arms which are disposed at different angleswith respect to one another can be assigned to each wheel side of anaxle between the control rod and the adjusting link.

According further to the present invention, the setting on the swivelshaft can be determined by the position of the wheel-carrier-side jointof the lower suspension link and by the position of wheel-carrier-sidejoint of the tie rod and a ratio of the camera to the toe-in on thewheel can be determined in a defined manner.

According further to the present invention, the swivel axis has asetting of alpha α=90° for achieving a toe-in adjustment on the wheel.

According further to the present invention, the adjusting element isdisposed in a plane arranged below the wheel spin axis and is connectedwith a two-arm lever which extends in an approximately vertical planeand is connected by means of its free end facing away from the bearingof the adjusting element with the control rod which is linked to thewheel carrier by way of the bearing above the wheel spin axis.

According further to the present invention, an adjusting device forabsorbing the suspension travel is connected with the suspension link ofeach wheel side of an axle arranged below the wheel spin axis, theadjusting device being connected by way of one pressure piperespectively with a chamber of the hydraulic cylinder.

The principal advantages achieved by the invention are that by thelinking of the suspension element to the wheel carrier, which isseparate from the control rod of the adjusting device, the forces,particularly the longitudinal forces, can also be absorbed separately,so that a wheel adjustment, such as a camber, a toe-in and a toe-out, isto be carried out which is not affected by it. As a result, a fasterbuild-up of side force takes place, particularly during cornering and/orlane changes. During straight-ahead driving and particularly inconnection with high speeds, a lower tire pressure may be used as aresult of minimal wheel adjustment changes by way of the springdeflection, which clearly increases the comfort level.

The adjusting device for the wheels of an axle is constructed such thatis can be used for the rear axles as well as for the front axles. Awheel adjustment takes place in a simple manner by way of a hydrauliccylinder, but may also take place by way of a motor, such as an electricmotor or a motor that is driven in another manner.

By way of a rocker lever disposed on the wheel carrier by means of aball joint, the control rod of the adjusting device as well as asuspension link are arranged to be pivotable about a horizontal axiswhich extends in the longitudinal direction of the vehicle. This doublebearing results in an absorbing of the longitudinal forces only by wayof the link bearing, and the tie rod bearing is free of loads resultingfrom these forces.

The connection of the control rod of the adjusting device with theadjusting link may take place by means of a two-armed supported lever.This lever then provides the possibility of determining the wheeladjusting paths in which the angle between the two lever arms, which areat an angle, is enlarged or reduced. As a result, the wheels can beadjusted in different fashions during the driving operation which is anadvantage particularly during cornering in order to build up differentcornering forces.

The adjusting device is also suitable for vehicles with rear wheelsteering in the case of which, by way of the lower suspension link, atie rod for a steering gear is also held on the wheel carrier.

In the case of vehicles with a rear engine, there is, for reasons ofspace, no room for an adjusting device arranged above the wheel spinaxis. This adjusting device will then be arranged below the wheel spinaxis, and a connection with the control rod arranged above the wheelspin axis will then take place by means of a deflecting lever.

The adjusting element, such as a hydraulic cylinder or a motor, may becontrolled by means of an electronic control unit which processes theindividual driving parameters. The individual driving parameters may beused as well as especially combined driving parameters and all drivingparameters together.

As a function of the wheel adjustment with respect to suspensionmovements of the wheel, the lower suspension link, for example, may beconnected with a device which absorbs the spring travel andcorrespondingly controls the hydraulic cylinder to carry out wheeladjustment changes.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a frontal view of a wheel suspension system with an adjustingdevice according to an exemplary embodiment of the invention.

FIG. 2 is a lateral view of the wheel suspension system according toFIG. 1 with an illustrated swivel axis according to an exemplaryembodiment of the invention;

FIG. 2a is a top view of the wheel suspension system according to FIGS.1 and 2;

FIG. 3 is a frontal view of an exemplary embodiment of a wheelsuspension system according to FIG. 1 with a two-armed lever between theadjusting element and the control rod according to an exemplaryembodiment of the invention;

FIG. 4 is a diagrammatic representation of the wheel suspension systemaccording to FIG. 3;

FIG. 5 is a frontal view of another exemplary embodiment of theinvention showing a wheel suspension system with an adjusting devicearranged below the upper suspension link;

FIG. 6 is a view of another exemplary embodiment of the inventionshowing a wheel suspension system with two suspension links arrangedbelow the wheel spin axis;

FIG. 7 is a view of another exemplary embodiment of the inventionshowing a wheel suspension system for a vehicle having a rear engine, inwhich the adjusting element is arranged below the wheel spin axis; and

FIG. 8 is a representation of an adjusting device with a possiblecontrol by way of an electronic control unit illustrated by interruptedlines and in a further exemplary embodiment of the invention showing byway of a suspension adjusting arrangement illustrated by solid lines.

DETAILED DESCRIPTION OF THE DRAWINGS

For the active adjustment of the wheels 2 of an axle in the toe-in andtoe-out as well as the camber direction, a wheel suspension system 1comprises a device 3 with an adjusting element 4 which engages on thewheel carrier 6 by way of a control rod 5. A swivelling of the wheel 2takes place about an axis X--X which is determined by a joint 7 of alower wheel suspension link 8 as well as by a joint 9 of a tie rod 10.This axis X--X may be set at an angle α of 0° to 90° corresponding tothe desired adjusting values.

According to the embodiments of FIGS. 1 to 3, the control rod 5 of theadjusting device 3 is arranged to be situated above the wheel spin axis11 and adjacent to the upper suspension link 12. In the case of thisembodiment, the tie rod 5 of the adjusting device 3 is provided in aplane above the suspension link 12. Together with the adjusting device3, it may also be arranged in a plane below the upper suspension link 12which is shown in detail particularly in FIG. 5.

The control rod 5 as well as the upper suspension link 12 are held onthe wheel carrier 6 by way of a rocker arm element 13 which is connectedwith the wheel carrier 6 by way of a joint 14. For the connecting of thecontrol rod 5 with this element 13, a swivel bearing 16 is provided onthe free end of the first lever arm 15 with a position 18 that isaligned in the longitudinal direction of the vehicle and in anapproximately horizontal manner. The suspension link 12 is supported onthe free end of the second lever arm 17 by way of another swivel bearing18 which is approximately correspondingly aligned.

The connection between the control rod 5 and the adjusting element 4takes place either by way of a simple joint 19, as shown, for example,in FIG. 1, or by way of a two-armed intermediate lever 20 with two arms20a and 20b which are disposed at an angle β, as illustrated in FIGS. 3,4 and 6.

According to FIG. 3, the control rod 5 is connected on the wheel carrierside on the rocker arm element 13 with the adjusting element 4 by way ofthe lever 20 with the two arms 20a and 20b, which is showndiagrammatically in FIG. 4. This linking of the tie rod 5 permits analmost linear shifting of the control rod 5. The tie rod 21 which isconnected below the wheel spin axis 11 on the wheel carrier 6 isconnected with a steering gear which is not shown in detail.

According to the embodiment of FIG. 6, the suspension links 12 and 8 arearranged below the wheel spin axis 11 while being disposed above oneanother at a distance from one another, and the control rod 5 with theadjusting element 4 is provided above the wheel spin axis 11.

According to another embodiment according to FIG. 7, for achieving aclearance for the receiving of a motor between the wheels 2 of an axle,the adjusting device 3 with the adjusting element 4 is displaced in aplane below the wheel spin axis 11, in which case the control rod 5 ofthe device 3 is situated in a plane above the wheel spin axis 11. Aconnection of a piston rod 22 of the adjusting element 4 with the rod 5takes place by way of an approximately vertically standing two-armedlever 23 which can be swivelled about an axis 24 which is alignedhorizontally in the longitudinal direction of the vehicle.

A wheel position change takes place as a function of driving parameters,such as the steering angle, the speed, the lateral acceleration, thelongitudinal deceleration, the longitudinal acceleration, the yawingmoment and the suspension. The adjusting element 4, for example, thehydraulic cylinder or a motor, can be controlled corresponding to theseparameters. According to one embodiment, an adjusting element 4 isassigned to each wheel 2 of an axle. As a result, it becomes possible toadjust each wheel 2 separately, according to the requirements, forexample, during cornering.

A separate adjustment of the wheels 2 of an axle is also achieved bymeans of the two-armed lever 20 between the control rod 5 and theadjusting element 4 in that the two arms 20a and 20b of the lever 20 areset at different angles β with respect to one another and thus adifferent path transmission ratio is obtained from the left to the rightwheel.

Furthermore, as indicated in FIG. 8, it is also possible to use adouble-acting hydraulic cylinder 30 as the adjusting element 4. Thisadjusting element 4 has a continuous piston rod 31 which is connected tothe control rod 5 of the two wheels 2 of an axle. According to a firstembodiment of the control, indicated in FIG. 8 by solid lines, the lowersuspension link 8 has an adjusting device 43 absorbing the springtravel. This adjusting device 43 comprises one pressure pipe 34respectively which starts out from a pressure intensifying device 33 andleads in each case into a chamber 35 of the double-acting hydrauliccylinder, in which case the pressure of the medium causes a displacementof the piston and therefore a wheel adjustment.

According to another embodiment, an electronic control unit 40 isillustrated in FIG. 8 by interrupted lines. This electronic control unit40 essentially comprises a control device 36 to which the drivingparameters are fed individually, combined or all together and fromwhich, on the output side, corresponding signals are supplied to thepump 37 which then leads the medium to the two chambers 35 and 38.Since, in the case of rear wheel steering, these driving parameters areavailable on the vehicle, it is possible without any high expendituresto adjust the wheels of an axle as a function of these parameters.

Although the invention has been described and illustrated in detail, itis to be clearly understood that the same is by way of illustration andexample, and is not to be taken by way of limitation. The spirit andscope of the present invention are to be limited only by the terms ofthe appended claims.

I claim:
 1. An arrangement for the active camber and toe adjustment of amotor vehicle wheel by way of an adjusting device comprising anadjusting element, in which suspension links are linked to a wheelcarrier, and swivellably held on the vehicle body, said adjustingelement, by way of a connected intermediate element is connected withthe wheel carrier while acting upon the wheel carrier in an adjustingmanner, wherein the intermediate element, by way of a central balljoint, is linked directly to the wheel carrier in a tiltable manner, anda control rod of the adjusting device is connected with a first bearing,and the suspension link is connected with a second bearing, theadjusting device comprising a hydraulic adjusting element which isconnected with the control rod and being constructed to be capable ofmoving in and out while influencing the position of the wheel by way ofan electronic control unit for forced wheel position changes as afunction of driving parameters, including at least one of: thesuspension travel, the lateral acceleration, the speed, the longitudinalacceleration, the deceleration, yawings and steering angles, and whereinthe wheel is adjustable about a swivel axis formed below the wheel spinaxis by a wheel-carrier-side tie rod joint and a wheel-carrier-side linkjoint.
 2. An arrangement according to claim 1, wherein the control rodis held on the intermediate element which is linked to the wheel carrierand which holds on an upper free end of the intermediate element thecontrol rod in the swivel bearing with an axis in an articulated manner,and supports on a lower free end of the intermediate element thesuspension link in the bearing with a swivel axis.
 3. An arrangementaccording to claim 1, wherein the control rod is held on theintermediate element which is linked to the wheel carrier and whichsupports on an lower free end of the intermediate element the suspensionlink in the swivel bearing, and holds on a upper free end of theintermediate element the control rod in the bearing in an articulatedmanner.
 4. An arrangement according to claim 1, wherein between theadjusting element and the control rod, an intermediate lever is arrangedwhich comprises two arms which are disposed at an angle with respect toone another.
 5. An arrangement according to claim 4, wherein theintermediate lever with the arms which are disposed at different angleswith respect to one another, is assigned to each wheel side of an axlebetween the control rod and the adjusting link.
 6. An arrangementaccording to claim 1, wherein the setting of the swivel shaft can bedetermined by the position of the wheel-carrier-side joint of the lowersuspension link and by the position of the wheel-carrier-side joint ofthe tie rod, and a ratio of the camber to the toe-in on the wheel can bedetermined in a defined manner.
 7. An arrangement according to claim 1wherein the swivel axis has a setting of α=90° for achieving a toe-inadjustment on the wheel.
 8. An arrangement according to claim 1, whereinthe adjusting element is disposed in a plane arranged below the wheelspin axis and is connected with a two-armed lever which extends in anapproximately vertical plane and is connected by means of its free endfacing away from the bearing of the adjusting element with the controlord which is linked to the wheel carrier by way of the bearing above thewheel spin axis.
 9. An arrangement according to claim 1, wherein anadjusting device for absorbing the suspension travel is connected withthe suspension line of each wheel side of an axle arranged below thewheel spin axis, the adjusting device being connected by way of onepressure pipe respectively with a chamber of the hydraulic cylinder. 10.An arrangement according to claim 8, wherein, an adjusting device forabsorbing the suspension travel is connected with the suspension link ofeach wheel side of an axle arranged below the wheel spin axis, theadjusting device being connected by way of one pressure piperespectively with a chamber of the hydraulic cylinder.
 11. Anarrangement according to claim 3, wherein between the adjusting elementand the control rod, an intermediate lever is arranged which comprisestwo arms which are disposed at an angle with respect to one another. 12.An arrangement according to claim 11, wherein the intermediate leverwith the arms which are disposed at different angles with respect to oneanother, is assigned to each wheel side of an axle between the controlrod and the adjusting link.
 13. An arrangement according to claim 12wherein the swivel axis has a setting of α=90° for achieving a toe-inadjustment on the wheel.
 14. An arrangement according to claim 6 whereinthe swivel axis has a setting of α=90 ° for achieving a toe-inadjustment on the wheel.